https://www.cnblogs.com/thomas-fan/p/15914830.html

CentOS7 默認(rèn)安裝了 openjdk 1.7 和 openjdk1.8,這里以安裝 openjdk11 為例

1. 查看當(dāng)前有幾個 jdk 版本

   alternatives --config java
   
   
   ---------------------------
   共有 2 個提供“java”的程序。
   
     選項(xiàng)    命令
   -----------------------------------------------
      1           java-1.7.0-openjdk.x86_64 (/usr/lib/jvm/java-1.7.0-openjdk-1.7.0.261-2.6.22.2.el7_8.x86_64/jre/bin/java)
   *+ 2           java-1.8.0-openjdk.x86_64 (/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.262.b10-1.el7.x86_64/jre/bin/java)

2. 下載

   wget https://download./java/GA/jdk11/9/GPL/openjdk-11.0.2_linux-x64_bin.tar.gz
   tar -zxvf openjdk-11.0.2_linux-x64_bin.tar.gzmv jdk-11.0.2/ /usr/local/

3. 使用 alternatives 安裝

   alternatives --install /usr/bin/java java /usr/local/jdk-11.0.2/bin/java 3

4. 使用 alternatives 切換

   alternatives --config java
   =============================
   共有 3 個提供“java”的程序。
   
     選項(xiàng)    命令
   -----------------------------------------------
      1           java-1.7.0-openjdk.x86_64 (/usr/lib/jvm/java-1.7.0-openjdk-1.7.0.261-2.6.22.2.el7_8.x86_64/jre/bin/java)
   *+ 2           java-1.8.0-openjdk.x86_64 (/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.262.b10-1.el7.x86_64/jre/bin/java)
      3           /usr/local/jdk-11.0.2/bin/java

5. 完成